Adjustable engineering curve



July 15, 1947.

c. LUNDBERG ADJUSTABLE ENGINEERING CURVE Filed July 17, 1944 INVENTOR. Char/e s Lun a bery ATTORNEY Patented July 15, 1947 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to an improved adjustable drafting or engineering curve, and its leading object is to provide a device which includes a flexible ruling edge, a base blade or bar forming a straight edge to accurately locate the device upon a drawing sheet in process of development, and a series of adjustable rods for controlling the curvature of the flexible ruling edge, which are adapted to be secured in selected adjusted positions by means of clamping posts mounted to turn on the base.

Another object of the invention is to provide a device of this character with adjustable rods which are pivotally connected at their ends to one side of the flexible curve, and which slide through posts adapted to freely turn on the base, so that the rods will adjust themselves to the various curved positions assumed by the flexible ruling edge, the posts being of uniform height and adapted to permit of the reversal of the flexible and adjustable curve, so that a predetermined curve may be produced on both sides of a given drafting layout, by simply inverting the device, so that the normally upper ends of the guide posts will ride on the drawing paper or board.

With the above and other objects in view the invention consists in certain new and useful constructions, combinations and arrangements of parts, clearly described in the following specification, and fully illustrated in the drawings, in which:

Fig. 1 is a plan view of the device, showing the flexible curve element adjusted to produce an engineering curve, and illustrating the normal position of the base.

Fig. 2 is a detail cross sectional view, taken on line 2-2 of Fig. 1, looking in the direction of the arrows.

Fig. 3 is a detail cross sectional view, taken on line 33 of Fig. 1, looking in the direction of the arrows.

Fig. 4 is an end view, showing the device inverted.

Referring to the accompanying drawings illustrating the practical embodiment of my invention 5 designates the base, which may be formed of metal or any other suitable material, and which is formed with parallel and bevelled straight edges 6 and I,

On the base blade 5 a plurality of guide posts 8 are arranged, and these posts are shown to be spaced equal distances from each other. The lower end of each guide post has a cylindrically reduced stud 9, which extends through a bearing hole formed in the base blade, and is retained 2 in position by flaring or riveting the stud 9 against the lower end of the bearing hole, which is flared for this purpose. This coupling is such as to permit each of the guide posts to freely turn on the base blade 5.

Each of the posts is formed with a transverse hole I0, in which the rod I I is adapted to slide, and this rod is clamped against sliding movement, by means of the set screw I2, which is threaded through the side of the post to clamp the rod..

The lower end of the post engages the upper surface of the base blade, and the riveted end of the stud of the post is disposed flush with the bottom surface of the blade, or in some cases may be inserted from said bottom surface. The upper ends of the posts are flat, and all these upper ends are disposed in the same plane.

The forward ends of the rods II are pivotally connected to the U-shaped hinge connector I3, and this is fastened, as by the rivet or screw I4, to the flexible ruling edge or member I5, intermediate of the parallel longitudinal edges I 541 and I5b of thi member. The width of this flexible ruling edge or member is equal to the combined height established by the base blade and the posts thereon, so that the device may be inverted, or placed in the position shown in Fig. 4, and supported by the outer ends of the posts and the ruling edge I5b.

In using the device the base blade is first positioned with relation to the drafting work being developed, and the flexible member I5 is flexed so that it will assume the curve required, and as it is flexed the rods are clamped by the set screws, so that the member I5 will retain the curve into which it has been shaped.

The set screws are all released from clamping position, when the flexible member I5 is flexed to the desired curve, and as this is done the ends of the rods will pivot on the side of the flexible ruling edge or member I5, and the posts will pivot on the base blade. This double pivotal movement permits of a free bending or curvin of the flexible member, and by clamping the rods the required curve may be maintained.

Due to the uniform height of all of the posts and the fact that the width of the flexible ruling edge or member equals the combined height of the blade and the posts, it is possible to reproduce a curve on the opposite side of a drawing, or in different relation thereto, with the exercise of careful judgment.

Due to the number of supporting rods used, the flexible curve will not bend when a pencil or ruling pen is moved against the outer and ruling surface thereof. The combined weight of all the parts is such that the device may be easily located with reference to drawings of ships, docks, railroads, roads, or any other engineering layout, and will retain its position against accidental shifting.

It is understood that I am not limited to the exact dimensions and proportions indicated in the drawings, but that any desired or needed changes in the choice of material, the proportion and detail construction of the parts, may be made without departing from the scope of the'invention as defined in the claims forming a part of this disclosure.

Having described my invention I claim as new:

1. A drafting device consisting of a base blade having a series of equally spaced bearing holes therein, a post mounted to turn in each bearing hole, the posts having fiat upper ends and being of equal height, a flexible curve member having a width equal to the combined height of the posts and base, rods slidable through the post and having pivotal connection with one side of the flexible curve member midway of the edges'thereof, and a set screw threaded through each post to clamp the rod engaging the same, whereby the adjustable flexible curve may be retained in any curved condition, and the device may be operated with the base resting directly on the drawing work or with the upper ends of the posts inverted and directly engaging the drawing work and curves reproduced in matching relation to each other by suchinversion.

2; An engineering drafting curve,.co1nprising a 4 base having straight edges on opposite sides thereof, a series of posts connected to the base in 1ongitudinally spaced relation and having flat upper ends disposed in a common horizontal plane parallel to the base, a series of rods slidable through the posts intermediate of their upper and lower ends, a flexible rulingblade, pivotal connections between the outer ends of the rods and the inner side of the flexible ruling blade, said flexible ruling blade having a width equal to the distance between the bottom face of the base and the upper ends of the posts, and set screws threaded through the sides of the posts against the rods to hold the rods in various adjustments on the posts, the posts being adapted to be inverted so that their upper ends will engage the Work, whereby the drafting position of the adjusted flexible ruling blade may be reversed on the work.

' CHARLES LUNDBERG.

7 REFERENCES CITED The following references are of record inthe file of. this patent:

UNITED STATES PATENTS 

